Improvement in lifting-jacks



I. Y. THU RSTON.

LIFTING-J'ACKS.

NM 75 9Q Patented. May 2,1876.

UNIT D STATES PATENT QFFIGEO JOHN Y. THURSTON, OF MEDFIELD, MASSACHUSETTS.

IMPROVEMENT m LlFTlNG-JACKS.

Specification forniing part of Letters Patent No. 176,960, dated May 2, 1876; application filed i April 4,1876.

invented anew and 11D[)IOVGtLLiftlllgJttck,Of

. which the following is a specification:

Figure 1 represents a sectional .sideeleva tion of my improved lifting jack, and Fig. 2 a top view of the same. 5

Similar letters ofreference indicate corresponding parts.

My invention relates to an improved liftingjack of simple and effective construction; and it consists of a sliding ratchet-bar operated by a spring-bolt lever, and retained bya safetyspring pawl.

In the drawing, A represents a'suitable casin g or frame of my jack, in which the liftingpost or ratchet-bar B slides in suitable guides. A lever-handle, O, is fulcrumed to casing A and provided with a spring-bolt, D, that en gages, by its wedge-shaped end, the teeth of the ratchet-bar, so as to lift the same by hoisting the weight. A spring-pawl, E, is pivoted to the upper part of easing A at the rear end of the same, and intended to retain the ratche tbar during the time when the lever is carried 1'1 'for engaging the next tooth. The springbolt D slides, by its wedge shape, back into the socket-recess of the handle when the lever isswnng up, but engages the teeth of the ratchet when carried down. A small sliding bolt, F, acts on the rear end of the springpawl E, and releases the same from the ratchetbar when it is desired to let the bar back into the casing.

The leverwith lifting springbolt is very JOHN Y. THURSTON. Witnesses: y

D. HOIZINGTON, F. H. MERRILL. 

